The invention pertains to signal jamming systems, carried by manned or unmanned aircraft including missiles, for the avoidance of position locating, tracking and fire control radar.
The subject matter of the present application is related to a co-pending application, Ser. No. 225,698, filed Jan. 16, 1981 by Walter E. Buehler, David C. Lunden and Michael J. Lewis (BASC-1-0634), entitled Apparatus and Method for Ventriloqual-Like Jamming of Radar Including an Aircraft Towed Single Wire Transmission Line and Wave Launcher Therefor.
The use of radar signal jamming equipment carried onboard manned and unmanned aircraft to mask the aircraft's position from position locating, tracking and fire (weaponry) control radar is one of a number of known radar avoidance techniques that fall in the broader field of electronic counter measures (ECMs). Existing jamming techniques are primarily effective in denying the radar equipment range information, i.e., the distance between the radar and the target aircraft. However, the transmission of the jamming signal, emanating as it does from the aircraft, enables some radar systems to home-in on the source of the jamming signal, which is typically a noise signal in the frequency band of the radar, and thereby acquire accurate information representing the angular position of the aircraft. This angle information alone, even without range determination, is sufficient to allow for many types of weaponry, aimed by fire control radar, to reach and destroy the target aircraft. Thus, the mere generation and transmission of a noise jamming signal is not totally effective and providing the desired masking of the aircraft to the tracking radar.
The above-identified related application Ser. No. 225,698, discloses and claims a ventriloqual-like jamming method and apparatus by which the jamming signal deceptively emanates from a position which is removed at a safe distance behind the target aircraft. The present invention concerns an improvement to that method and apparatus.
In particular, it is an object of this invention to provide a ventriloqual-like jamming system of the type characterized in the related application Ser. No. 225,698, that has the capability of hiding the excess signal energy associated with a return radar signal reflected off the target aircraft, and which energy might otherwise provide a trackable signal source revealing the position of the target aircraft.